Page 532 - Marine Structural Design

508 Part IY Shvctural Reliability

What?
A substantial amount (if not the majority) of the damage is unpredictable and due to the
unanticipated ‘erroneous’ actions and inaction’s of people.
Current experience also indicates that the majority of damage that is associated with accidents
(collisions, dropped objects) is discovered after the incident occurs. About 60% of damages
due to fatigue and corrosion are detected during routine inspections. However, the balance of
40% is discovered accidentally or during non-routine inspections.
How?
The methods to be used in FPSO inspections are visual. In one form or another, these methods
are primarily focused on getting an inspector close enough to the surface to be inspected so
that he can visually determine if there are significant defects or damages. However, ultrasonic
gauging, magnetic particle, radiographic, and other nondestructive methods, are sometimes
necessary for structures.
When?
There are no general answers to the timing of inspections. The timing of inspections is
dependent on:
The initial and long-term durability characteristics of the FPSO structure
The margins that the operator wants in place over minimums so that there is sufficient time
to plan and implement effective repairs
The quality of the inspections and repairs
The basis for maintenance - ‘on demand’ (repair when it ‘breaks or leaks’ or
‘programmed’ (repair or replace on standard time basis)
Who?

Experience has adequately demonstrated that the single most important part of the inspection
system is the inspector. The skills, knowledge, motivation, and integrity of the inspector are
critically important. Equally important are the organizational influences exerted on the
inspector, the procedures and processes that he is required to follow, the environments in
which he must work, and the support hardwarelsystems that are provided to perform his work.
Thus, the inspector is significantly influenced by 1) organizations, 2) procedures, 3) hardware
(facilities), and 4) environments.
Much has been learned about how to improve the effectiveness and efficiency of the inspector.
It is important that the inspector be recognized as a part of the system, as new inspection
systems are designed.
Why?

The inspection should have objectives at several levels: first, it should provide the general
information and knowledge about the in-service structures for fitness for purpose evaluation.
Second, it should detect the damage/defects so effective and efficient maintenance and repair
programs can be implemented to correct these damageddefects (quality control and assurance).
Third, it is a safety control tool to prevent the failure or loss of the in-service structures during
the inspection interval (safety control and assurance).